1. Technical Field
The present invention relates to a short optical pulse generator, a terahertz wave generation device, a camera, an imaging apparatus, and a measurement apparatus.
2. Related Art
In recent years, a terahertz wave which is an electromagnetic wave with a frequency of 100 GHz or more and 30 THz or less has attracted attention. The terahertz wave may be used for, for example, imaging, a variety of measurements such as spectroscopic measurement, nondestructive inspection, and the like.
A terahertz wave generation device generating the terahertz wave includes, for example, a short optical pulse generator which generates an optical pulse with a pulse width of about subpicoseconds (several hundreds of femtoseconds), and a photoconductive antenna which generates a terahertz wave by being irradiated with the optical pulse generated by the short optical pulse generator. Generally, a femtosecond fiber laser or a Ti-sapphire laser is used as a short optical pulse generator generating an optical pulse with a pulse width of about subpicoseconds.
For example, Japanese Patent Application No. JP-A-2009-158983 discloses a fiber laser capable of generating a linearly chirped high power parabolic pulse by using a fiber doped with a rare-earth element.
However, in the fiber laser disclosed in JP-A-2009-158983, it is necessary to increase fiber length in order to give a predetermined frequency chirp to an optical pulse, and this increase in fiber length results in an increase in the size of the device.